The video chat mobile app Google Duo can now call to even those of your contacts who don't have the app installed on their devices. However, this feature is currently restricted to Android phones and it is also possible that the feature is available only for few users on your contact list, the reason for which is currently unknown.

A Reddit user noticed this new feature and it was first picked up by Android Police. The option to call any of your contacts is included in the latest update, with an ‘Instant App’ like experience called App Preview Messaging that’s part of Google Play services. This will let the Android users answer the call through Duo.

It works almost exactly like a normal Duo call, including the Knock-Knock feature that lets you see the preview of the caller before you pick it up. Users on the other end can receive the call to answer it, change cameras, mute the microphone, hold like a regular duo call and more. There’s even a persistent notification icon that allows you to switch to another app and back again, while it is still connected.

Furthermore, you can also block a caller from contacting you again. However, if the someone wants to make a call without Duo installed, then they have to first install the app.